Distillation apparatus



Nov. 14, 1939. K. c. D. HICKMAN DISTILLATION APPARATUS Filed June 29,1938 2 Sheets-Sheet l Ae/me 2% C Qfi/ckmon INV TOR BY Wm H. M

ATTORNEYS Nov. 14, 1939.

K. c. D HICKMAN DISTILLATION' AP'PARATus 2 Sheets-Sheet '2 Filed June29, 1938 2 tion.

' Patented Nov. .14, 1939 PATENT" OFFICE 2,180,053] prsrnaarrrorzvAPIARATUS Kenneth c. n. Hickman, Rochester, N. Y., as- ,signor toDistillation Products, Inc Rochester,

N. Y., a corporation of Delaware In Great Britain July 29. 193':

Application June 29, 1938, Serial No. 216,551

.8 Claims. (01'. zoz-zsei This inventionrelates to improved means for-The inven- K distilling under reduced pressure. tion in particularrelates to improved high vacuum unobstructed path distillationapparatus.

In my United States application 99,632, filed September 5, 1936, I havedescribed distillation apparatus wherein the distilland is caused .toflow in the form of a thin film at high speed over the distillation orvaporizing surface of a'higl 10 vacuum, evaporative or short path still.Thisis accomplished by introducing the distilland in liquid state onto aheated rapidly rotating sur-' face. The liquid is caused to flow to theperiphery of the heated surface by centrifugalforce.

1 In the same application I also describe the feature of employing arotating condensing surface and causing the liquid condensate to flow tothe periphery of the condensing surface by centrifugal force.

20 In both cases the liquid -which'was forced to the periphery bycentrifugal action, was caught in a gutter suitably located aroundthespinningsurface. The constructions have outstanding advantages overprior art methods of distilla- This invention has for its object toprovide improved vacuum distillation apparatus of this general nature.Another object is to provide improved centrifugal, short pathdistillation appa- 30 ratus Another object is to provideimproved methodsof removing organic oils or liquids from rotating high vacuumdistillation surfaces. Other objects will become apparent as thedescription proceeds. I a

35 1 In the drawings. and description, I have set 1 forth'severalof thepreferred embodiments of iny, invention. However, it is to be understoodthat they are described for the purpose of illustration and that myinvention is not limited 40 thereto.

In the drawings, wherein like numbers refer to like part8: I

,Figs. 1, 3 and 6 arefragmentaryvertical sections of different liquidremoval means; I

45 Figs. 2, 4 and 7 are fragmentary perspective views, partly in sectionof the apparatus illus-' tratedin Figs. 1, 3 and 6 respectively;

,Fig.-5 is a fragmentary perspective partly in section of a modificationof the liquid removal in means illustrated in Figs. 3 and 4; 1

Fig. 8 is a vertical" ection ofa modification of the removalmeansillustrated .in Figs. 6 and '7; Fig. 9 is' a fragmentary elevation ofanother type of liquidremoval means; I 55 Fig. 10 is a viewtaken on lineIll-l of Fig. 9;

Fig. 11 is a vertical section through a still provided with acentrifugal distilling plate and a liquid removal device embodying theprinciples of my invention;

Fig. 12 is a view taken on line l2-l2 of Fig. 11;

Fig. 13 is a fragmentary perspective of the scraping device of Fig. 11.

I Fig. 14 is a vertical section of the moving parts of a centrifugalstill provided with rotating'vaporizing and condensing plates equippedwith the various removal devices illustrated in Figs; 3, 8 and 9;

Fig. 15 is a fragmentary vertical section of slight modification showinga "turned edgecon struction which does not obstruct passage oil 15 gasfrom between the rotating plates.

In Figs. 1 and 2 numeral l6 designates an approximately horizontal shaftupon which is mounted a. vertical circular plate l8, the periphery ofwhich is turned back to form a gutter having an approximatelysemi-circular cross section as indicatedat 20. Numeral 22 designates aconduit by means of which liquid distilland is introduced onto thecenter of plate l8. Nu- 'meral 24 indicates a conduit, the end 26 ofwhich 5 protrudes into the turned edge 20, and is in light .contact withthe bottom of the gutter formed by the turned edge.

During operation of a still provided with this "equipment disc I8 iscaused to rotate at rela- 30 I tively high speed by means of forceapplied to shaft l6 and liquid distilland is simultaneouslyintroducedthrough conduit 22', the liquid flows onto the center of disc l8. It isthen immediately forced to the periphery .by centrifugal force. Duringthe passage over the plate it is in the form of a very thin film.- Platel8 being a vaporizingsurface will 'be heated .by means (notshown) todistillation temperature. The thin film is'th'ereforeeffectivelydistilled during its 40 passage over the plate. Undistilledresidual liquid passes into the gutter formed by turned edge I 20. As itaccumulates it is caught in the end 26 of conduit 24 and flows by its'own inertia -and/or gravity through the conduit and can be conveyed toany required remote point, or to uid'will accumulate until it has asufficient depth 'to be caught by the end of the conduit'.

The construction shown in Figs. 3 and 4 is similar to that shown inFigs. 1 and'2, the .dif-

ference being in the construction of the scoop or liquid pick-up means.In this construction conduit 24 is enlarged at the end as indicated at28. A small scoop or scraper 30 is mounted in the open end of theconduit and extends into the gutter formed by turned edge 20. This scoopis shaped somewhat similar to the hollow end of a pen point or a spoon.It points in a direction opposite to that in which the disc I 8 rotates.It may be in actual contact with the turned edge or may merely be inclose proximity thereto.

During rotation of plate I8 liquid which passes into 20 is effectivelycaught by the scooping action of point and is. conveyed into removalconduit 24. The enlarged portion 28 effectively catches any small amountof spray or droplets.

Referring to Fig; 5, numeral 36 designates a funnel shaped enlargementat the end of conduit 24. The upper open portion of 36 is oval andextends into close proximity to the turned edge 20. A semi-circularscoop 38 protrudes from the center and is in light contact with thegutter. A plurality of semi-circular vanes 40 are mounted within 36.

The operation and,construction of the appa-' ratus of Fig. 5 is quitethe same as that of Figs. 3 and 4. However, the construction of member36 and provision of vanes 40 more effectively assures that allsplashings are caught and removed by the conduit 24.

In Figs. 6 and '7, numeral 46 designates the centrifugal plate of a highvacuum still. The periphery is not turned as in the previous figures,but extends into an annular gutter 48. Numeral 50 designates a scoop orscraper which isprefer ably in light contact with the surface of disk 46and which is connected to removal conduit 24.

During operation liquid introduced through conduit 22 is spun to theperiphery of plate 36 by centrifugal action. As soon as the liquidreaches scoop 50 it is scraped or wiped up from the surface of the disc.The removed liquid then flows into conduit 24 connected to the scoop.Any liquid which is not removed by the scoop is caught in gutter 48 fromwhich it may be removed by a conduit (not shown) connected to the basethereof. This is used only as a secondary guard to catch the smallportions of distilland .which escapes the main collecting mechanism 50.Contact between scoop 50 and the plate should be resilient and can bestbe maintained by a spring.

It has been found that with speeds of about 3000 R. P. M. the liquidwill proceed outward at speeds of between 1 and 100 cm. per secondaccording to the rate of supply and the dimensions of the p ate.Manifestly if the collecting tool 50 has a width greater than thedistance of travel of the distilland during one rotation, substantiallythe whole quantity of liquid residue will be caught in the collectingscoop.

Instead of using one device 50, a plurality of such devices may be used.This expedient is il-- lustrated in Fig. 8 where two scoops 52 and 54,similar to 50 of Fig. 6, are employed. The use of a plurality of scoopsor of a single extra wide scoop, preferably divided by partitions, moresurely removes residual liquid and therefore makes guard ring 48unnecessary.

Referring to Figs. 9 and 10, numeral 46 indicates a plate having a flatperiphery as described in connection with Figs. 6-8. Numeral 60designates an enlargement at the end of conduit 24,- the central portionof which is depressed. The

walls 62 and 64 and the bottom 65 01 th s dcinto a slot in the peripheryof plate 88. 'head of scraper 94 is the same shape as the V- Theenlargement extends beyond the depression at I2 to form a shield.

During operation the plate 46 is rotated in the directon indicated.Liquid is introduced onto the center of the plate through conduit 22.Undistilled liquid is thrown to the periphery by centrifugal force whereit is scraped or wiped from the plate by one or more of the surfaces 62,64 and 66. This removed liquid flows along the gutters 68 and I0 andinto conduit 24. Droplets are caught by shield 12 and conveyed toconduit 24 in a similar manner.

Referring to Figs. l1, l2 and 13, numeral designates a closedcylindrical still casing and numeral 82 a plurality of lugs integraltherewith. Similar lugs 84 support an adjustable ring 86. This ring isprovided with an annular V- shaped gutter which surrounds vaporizingplate 88 and is close to its periphery. Ring 86 is split at so that theclearance between it and the periphery of plate 88 can be varied. Aconduit 92 communicates with the V-shaped gutter at a tangent and servesto carry away liquid contained therein. Numeral 94 designates a cleftscraper, the cleft portion of which slips over plate 88 and. thecorresponding uncleft portion of which fits The shaped gutter in ring 86and during rotation extends into this gutter and makes resilient contacttherewith.

During operation the plate 88 is caused to rotate and the ring 86 isadjusted at 90 so that liquid introduced at conduit 22 is received intoring 86 without splashing and so that scraper 94 smoothly engageswiththe V-shaped gutter. The liquid is partly distilled in its travelover plate 88 as described above. Undistilled residue is thrown into theV-shaped gutter. The liquid in the gutter isscraped or wiped up by eachrotation of scraper 94 and pushed or thrown into removal conduit 92.

The action of scraper 94 is not definitely understood but it is thoughtthat a minute wave of liquid is formed in front of the scraper and thatthis small body of liquid passes into the conduit 92 as it passes overthe opening between the gutter and the conduit.

In Fig. 14 reference numeral I00 designates a vaporizing surface and I02a condensing surface located at a short distance therefrom. Surface I00is punched out at the center to form a truncated cone I04 into whichextends conduit 22. A plate I06 integral with shaft I6 is of smallerdiameter than the punched out portion of plate I00 so as to leave aspace I08 therebetween. Plate I06 supports plate I00 by a plurality ofsupports extending across space I08. These supportshave notbeen shown inthe drawingsbecause it would impair their clearness. One side of theplate I00 is heated by means of an electrical heating element IIO,- theheat of which is reflected against the plate by reflector I I2. NumeralII4 designates a .scoop device similar to that illustrated in detail inFigs. 9 and 10. Numeral I I1 designates a cooling coil, one end II 6 ofwhich terminates near the center of plate I02 and the other end of whichis provided with the removal device II8 illustrated in Figs. 3 and 4,which extends into the turned edge I20. Numerals I22 and I24 designatescoop removal devices similar to those illustrated in Fig. 8.

Inoperating theapparatus illustrated'in Fig. 4 the system in which theplates are located is evacuated to the desired low pressure. Shaft I6 isthen caused to rotate at a suitable speed. Heating element "0 is putinto operation and liquid distilland is introduced through conduit 22onto the inside of cone I04. The liquid travels through space I00 andover the surface of( plate ,I00. Since the plate is heated todistillation 10 temperature the liquid distilland is distilled duringits passage thereover. Undistilled residue is removed by means of deviceIll. Vapors pass to plate I02 and 'are condenser thereon. The liquidcondensate is caused to pass to the periphery of plate I 02 due to itshigh speed of rotation. As the liquid arrives at the periphery of. theplate it is caught in scoops I22 and I24 and removed, from the still.

The condensing plate I02 must be maintained at a rather lowtemperature.This is accomplished by introducing a cooling fluid into coil I I 1which is located outside the still where it can be cooled. The fluidflows by gravity through conduit IIG to the center of plate I02, is then26 thrown by centrifugal force into turned edge I20,

is then caught in scoop I I8 and returned to cooling coil I I I bygravity. This cooling liquid should be of a suitable low vapor pressureso that it wil not interfere with the high vacuum distillation. Inconnection with Fig. 14 it will be noted that if both plates wereprovided with edges turned backtowardseach other there would be littlespace my invention is applied thereto. In a complete working setuptheplates will be mounted in a closed system which can be evacuated by aconduit connected thereto. Several pairs of plates can be mounted in thesame system or chamber.

While many of the figures are limited to vaporizing surfaces the sameexpedients are suitable for use in connection with the removal oivcondensate and/or cooling fluid from rotating condensing surfaces.Rotating condensing sur faces need not be used. The whole still assemblyhas not been illustrated since its construction is obvious. The surfacesare preferably nonhorizontal to permit the taking advantage of thepumping effect of the invention. The invention is applicable tohorizontal surfaces with many attendant advantages. When solids arecondensed a rotating condensing surface can be employed in conjunctionwith a scraper whichwill remove the solid condensate which can then bepermitted to whirl away into largeannular chambers at the periphery ofthe plate.

The-procedure is particularly useful in high vacuum unobstructed pathdistillations, i. e., where the condensing and vaporizing surfaces areseparated by substantially unobstructed space and a high vacuum such asa pressure below approximately 1 mmfexis'ts therebetweem, High vacuumshort path conditions erally satisfactory, namely, scribed where thedistance bet een the two surfaces is short and of the order of less than1 of the plate.

the gutter.

e almost genillation as dethe system and the space between the disc andfoot and preferably about V to 6 inches. When the distance between thesurfaces is less than the mean free path the distfllat'ion is of a type.top of the plate. The liquid therefore has beenlifted a distance whichcorresponds to the radius This is advantageous where a plurality ofplates are employed in one still unit. The liquid removed at thetop ofthe plate can be-allowed to flow to the ceriter of the next plate whereitis again spun to the top of .the plate. This can be repeated anyrequired-number of times without necessitating the provision ofexpensive lifting pumps.

The collecting tools have a further advantage. When liquids arecollected in gutters, they flow, with considerable" slowness to thewithdrawal conduit connected to the gutter and tend to accumulate inrather large amounts. If the liquid is hot when it is removed from theplate considerable thermal-decomposition can take place during theperiod of time that it remains in Also cooling and corresponding heatloss take place. In addition the invention has the decided advantagethat' condensing and vaporizing plates can be placed much closertogether than is possible with gutter collecting means. Placing guttersat the peripheries of the plates materially restricts the space forremoval of gases from between the plates. By eliminating the gutters,the plates can be placed very close together. 'This results in extremelyhigh efficiency. Spraying and splashing is also greatly reduced.

What I claim is:

1. Vacuum distillation apparatus comprising in combination within aclosed system a nonhorizontal rotatable disc, means for heating thedisc, means fpr introducing liquid distilland onto the approximatecenter of the disc, means located 'at approximately the highest point ofthe disc for removing undistilled liquid residue from the periphery -ofthe disc before it has been thrown from the disc by centrifugal -force,-a condensing surface. located in close proximity to the disc andseparated therefrom by substantially unobstructed space and means forapplying a suction to the closed system whereby the pressure withinthesystem and between the disc and the condensing surface can be'reduced.

2. Vacuum distillation apparatus comprising in combination within aclosed system, an approximately, vertical rotatable disc, heating means10- for removing condensate" from the condensing surface and a conduitfor removing gases from the condensing surface. 7

3. Vacuum distillation apparatus comprising in combination within aclosed system, a. rotatable disc-shaped vaporizing surface, means forheating the surface, means for introducing liquid distilland onto theapproximate center of the surface, means for removing undistilled liquidresidue from the periphery of the surface where it is caused to flow bycentrifugal force, a condensing surface located in close proximity tothe vaporizing surface and separated therefrom by substantiallyunobstructed space and means for applying a suction to the closed systemwhereby the pressure within the system and between the disc and thecondensing surface can be reduced.

4. Vacuum distillation apparatus comprising in combination within aclosed system, a rotatable disc-shaped vaporizing surface heating meanslocated on one side of the surface, means for introducing liquiddistilland onto the approximate center of the opposite side of thesurface, a device located at the periphery of the surface which isadapted to remove. the liquid undistilled residue from the surface, aconduit connected to this device whereby liquid removed is carried away,a condensing surface located opposite that side of the vaporizingsurface upon which the distilland is introduced, which is in closeproximity to the vaporizing surface and separated therefrom bysubstantially unobstructed space, means for removing condensate from thecondensing surface and a conduit for removing gases from the system andthe space between the disc and the condensing surface.

5. Vacuum distillation apparatus comprising in combination within aclosed system, a rotatable disc, a heating element located on one sideof the disc and adapted to heat the disc by radiation to distillationtemperature, means for introducing liquid distilland onto theapproximate center of the opposite sideof the disc, a scraping device inlight contact with the same side of the disc at its approximateperiphery'which is adapted to remove liquid undistilled residue from thedisc, a conduit connected to the scraping device to carry away liquidthu removed from the disc, a rotatable condensing surface located at ashort distance from the disc andseparated therefrom by substantiallyunobstructed space, a scraping device in light contact'with thecondensing surface at its approximate periphery which is adapted toremove liquid condensate therefrom, a conduit connected to the scraperto carry away liquid condensate thus removed and a conduit forevacuating the system and the'space between the disc and the condensingsurface.

6. Vacuum distillation apparatus comprising in combination within aclosed system an approximately vertical rotatable disc, a heatingelement located on one side of the disc and adapted to heat the disc todistillation temperature by radiation, means for introducing liquiddistilland onto the approximate center of the opposite side of the disc,a scraping device in light contact with the same side of the disclocated at a point above the axis of the disc and at its approximateperiphery, which device is adapted to remove liquid undistilled residuefrom the disc, a conduit connected to the scraping device to carry awayliquid thus removed from the disc, 9. rotatable condensing surfacelocated approximately parallel to and a short distance from the disc andseparated therefrom by substantially unobstructed space, a scrapingdevice in light contact with the condensing surface which is located ata point above the axis of the condensing surface and at its approximateperiphery and which is adapted to remove liquid condensate therefrom, aconduit connected-to the scraper to carry away liquid condensate thusremoved and a conduit for evacuating the system and the space betweenthe disc and the condensing surface.

7. Vacuum distillation apparatus comprising in combination within aclosed system, a rotatable disc means for heating the disc, a conduitfor introducing liquid distilland onto the approximate center of thedisc, an annular gutter surroundingthe periphery of the disc and inclose proximity thereto, a scraper mounted upon the periphery of thedisc so as to make resilient contact with the bottom of the gutter, aconduit connected to the gutter at a tangent in such a manner as tocarry away liquid deposited therein by the scraper, a condensing surfacelocated in close proximity to the disc and separated therefrom bysubstantially unobstructed space, and a conduit for removing gases fromthe system and the space between the disc and the condensing surface.

" 8. Vacuum distillation apparatus comprising in combination within aclosed system, a rotatable disc the edge of which is turned to form anannular gutter having an approximately semicircular cross section, meansfor heating the disc, means for introducing liquid distilland onto 'theapproximate center of the disc, a scoop mounted so that it protrudesinto the gutter at the periphery of the disc whereby liquid therein isremoved, a conduit connected to the scoop for carrying away the liquidremoved from the disc, a condensing surface located near the disc andseparated therefrom by substantially unobstructed space, means forremoving condensate from the condensing surface and a conduit forremoving gases from the system and the space between the disc and thecondensing surface.

0. D. HICKMAN.

